TROPICAL SEA OF ​​PERU: CHARACTERISTICS, ECOSYSTEMS AND RELIEF - ENVIRONMENT - 2025

The tropical sea is the marine space influenced by the El Niño current, on the coast of the Pacific Ocean, north of Peru. This current constitutes the southern part of the Panama Current, which comes from the Gulf of Panama and later from Colombia.

The tropical sea, together with the cold sea, constitute the entire maritime space of Peru in the Pacific Ocean. This territory is officially known as the Sea of ​​Grau.

Mancora beach, Talara province, Piura department, Peru. Source: Mazter, from Wikimedia Commons

The tropical sea extends from the border with Ecuador on the lower line of Boca de Capones (3º south latitude) to the Illescas peninsula, in the department of Piura (5º south latitude). It constitutes the northern or northern region of the Sea of ​​Grau.

Due to the low latitudes and the influence of the El Niño current, the waters of the tropical sea are warm and with a very high biodiversity. Unlike the waters of the cold sea, characterized by its low temperatures and high productivity.

characteristics

The waters of the tropical sea are warm during all times of the year. Its temperature can vary between 19ºC and 22ºC in the hottest season of the year. This is due to its proximity to the equator and the influence of the El Niño current, formed by warm waters.

It has a low salinity due to the high rainfall of the tropical zone. Unlike the cold sea of ​​Peru, its nutrient content is low, so its productivity is lower.

The bluish color, the temperature and the abundant biodiversity of the tropical sea, make it an important tourist destination for Peru.

El Niño Stream

The El Niño current is the seasonal flow of warm equatorial waters that travel off the north coast of the Peruvian Pacific, in a north-south direction. This collides with the cold current that comes from the south and they deflect towards the west.

It has an important effect on the climate of Peru by generating regular or sudden rains and death events of large masses of plankton.

Marine-coastal ecosystems

-Manglars

The mangrove is a type of wetland that develops in areas influenced by the tides in which a mixture of salt and fresh water occurs. In Peru this type of ecosystem is restricted to the tropical sea. It covers a total area of ​​5870 ha, less than 0.01% of the national total.

Flora

Mangroves are vegetation formations with a predominance of different mangrove species: red mangrove (Rhizophora mangle), red mangrove (Rhizophora harrisonii), white mangrove (Laguncularia racemosa), black mangrove (Avicennia germinans) and pineapple mangrove (Conocarpus erectus).

Other arboreal plant species present in the mangroves are also the faique (Acacia macracantha), the tern (Caesalpinia paipai), the carob tree (Prosopis pallida), the palo santo (Bursera graveolens), the añalque (Coccoloba ruiziana), the ceibo (Ceiba trichistandra), lipe (Scutia spicata), palo verde (Parkinsonia aculeata), among others.

Some species of climbing plants and epiphytes also inhabit the mangroves. The pitaya, a liana of the genus Selenicereus sp., Bromeliads such as Tillandsia usneoides and some orchids of the genera Oncidium, Epidemdrum and Cattleya stand out.

Fauna

Mangrove roots serve as a substrate for many species of invertebrate echinoderms (Ophiothrix), crabs (Ucides), snails (Calliostoma, Theodoxus) and barnacles (Pollicipes).

In addition, some species are subjected to great extraction pressure for commercial uses. The bibalbos stand out, such as the black shell, hollow shell, donkey's foot shell (of the genus Anadara), the lampa shell (Atrina maura), the striped shell (Chione subrugosa) and the mussel (Mytella guyanensis). As well as prawns (Pennaeus spp.) And jaivas (Callinectes).

On the other hand, mangroves are a refuge for larvae and juveniles of a great diversity of fish species. Notable snook (Centropomus viridis), red snapper (Lutjanus guttatus), mojarras (Eucinostomus currani), mullet (Mugil spp) and catfish (Galeichthys peruvianus).

Large species such as the river crocodile (Crocodylus acutus) and the northwestern otter (Lutra longicaudis) also live among the mangroves.

The branches of mangroves and other tree species are used as roosts and nesting sites by a large number of bird species such as pelicans (Pelecanus thagus and Pelecanus occidentalis), the Chilean flamingo (Phoenicopterus chilensis), ibis (Eudocimus albus and Eudocimus ruber), the frigate bird (Fregata magnificens) and the cormorant (Phalacrocorax brasilianus)

-Intermarial ecosystems

Intermarial ecosystems are those that develop in a transitional space between terrestrial and marine environments. Specifically, it ranges from the highest to the lowest level influenced by the tides. On the Peruvian coast, this area is represented by sandy beaches, stony beaches and rocky coastlines.

Sandy beaches

It constitutes the least diverse ecosystem. Highlight a low diversity of macrobenthos. At the supralittoral level, the highest area, the road crab (Ocypode gaudichaudii) and the isopod Excirolana braziliensis are distributed.

At the intermediate level (mesolitoral zones) the crustaceans Callianassa garthi and Emerita analoga, and the mollusks Mesodesma donacium and Donax marincovichi are distributed. Other associated species are the polychaetes (Thoracophelia, Lumbrineris, Nephtys impressa and Hemipodus biannulatus).

The sandy beaches of the North Sea are characterized by very abundant populations of the filter snail Olivella columellaris.

Rocky coastlines

The rocky coastlines are very heterogeneous environments with a great variety of microhabitats, which favors an increase in the biodiversity of this ecosystem.

In the supralittoral zone, the gastropods Nodilittorina peruviana and the crustaceans Grapsus grapsus predominate.

While in the mesolitoral zone, located in the intermediate section of the rocky coastline, which presents a greater effect of the tides, the macroalgae meadows of the Porolithon, Enteromorpha, Hynea, Cladóphora and Gracilaria genera develop.

Regarding the fauna, the barnacles Jehlius cirratus and the bivalves Perumytilus purpuratus and Semimytilus algosus dominate.

Finally, in the infralittoral zone, the one that is always submerged, the following types of algae stand out: Gelidium, Hypnea, Gracilaria and Laurencia (red algae), Sargasum and Dictyota (brown algae), and Halimeda, Caulerpa, Ulva (green algae).

In addition, numerous populations of the barnacles Austromegabalanus psittacus and the polychaete Phragmatopoma moerchi are present in this area. Some species of actinias (Anthothoe chilensis and Phymactis clematis) can also be found.

Among the fish associated with these rocky littoral ecosystems, the car fish (Balistes polylepis), the carrot fish (Antennarius avalonis), the moray eel (Gymnothorax porphyreus), the drunken fish (Scartichthys gigas) and the trambollo fish (Labrisomos philipii) stand out.

Stony beaches

The stony beaches represent the transition zone between the sandy beaches and the rocky shores. These can be pebbled or sharp-edged beaches.

The characteristic fauna of these beaches is similar to that of the rocky coastlines. However, certain peculiarities stand out, such as the presence in the supralittoral zone of the isopods Ligia novaezelandiae, the polychaete Hemipodus biannulatus, and the crustaceans Pinnotherelia laevigata and Cyclograpsus cinereus.

In the mesolitoral zone inhabits the amphipod Prisogaster niger. While in the infralittoral zone the amphipod Tegula tridentata is found.

Marine ecosystems

Coral reefs

The most representative marine ecosystem of the tropical sea of ​​Peru is the coral reef. These constitute one of the ecosystems with the greatest biodiversity in the world.

Coral reefs are found in shallow seas, with warm temperatures (between 25 and 29 ºC), mainly in the tropical and subtropical zone of the planet.

Coral reefs are supported by a calcareous mass formed by cemented corals over millions of years. Corals grow on these complex structures, made up of colonies of polyps that establish a symbiotic association with photosynthetic zooxanthella algae.

In the coral reefs of the tropical sea of ​​Peru, different coral species coexist, in addition to a great diversity of other invertebrates and fish. Among the fish the families Serranidae, Pomacentridae, Labridae, Haemulidae, Diodontidae and Chaetodontidae predominate.

The high biodiversity associated with coral reefs is threatened by the effects of climate change. Increased temperatures, ocean acidification, sediment accumulation and increased concentration of nutrients are the main threats.

In the waters of the Eastern Pacific, the influence of the El Niño current is added. Due to the increase in water temperature, it has caused irreversible coral bleaching events.

Relief

The tropical sea of ​​Peru ranges from the low tide line to 200 miles out to sea. In this territory there are three different zones: the coastal, the neritic and the oceanic.

Coastal zone

The coastal zone ranges from the coastal marine zone to a depth of 30 meters.

Neritic zone

The neritic zone ranges from the 30-meter deep line to the limit of the continental shelf, approximately 200 meters deep.

In the tropical sea of ​​Peru, the neritic zone contains the continental base. This is 50 km wide at the height of the department of Tumbes and 40 km in front of the Sechura desert. Getting narrower at the southern end of the tropical sea.

Oceanic zone

The oceanic zone is one that is found after the limit of the continental shelf. This can reach thousands of meters deep.

The oceanic zone includes the continental slope, a depression to the west of the continental base that exceeds 6,000 m in depth. In this area are the underwater canyons, valleys or cavities on steep slopes, similar in appearance to the canyons on the earth's surface.

References

1. Sea of ​​Grau. (2018, October 3). Wikipedia, The Free Encyclopedia. Consultation date: 09:23, January 6, 2019 from
2. Ministry of the Environment. 2010. Fourth national report on the application of the Convention on Biological Diversity, years 2006-2009. Lima Peru.
3. Ministry of the Environment. 2014. Fifth national report on the application of the Convention on Biological Diversity, years 2010-2013. Lima Peru.
4. Rodríguez, LO and Young, KR (2000). Biological Diversity of Peru: Determining Priority Areas for Conservation. Ambio, 29 (6): 329-337.
5. Tarazona, J., Gutiérrez, D., Paredes, C. and Indacochea, A. (2003). Overview and challenges of marine biodiversity research in Peru. Gayana 67 (2): 206-231.